On the Internet, multimedia services such as streaming, videoconferencing, and Video On Demand (VOD) are becoming important components in information transmission. Unicast, which is a point-to-point transmission mode, cannot adapt to transmission features of multimedia services, namely, single-point transmission and multi-point reception. In this case, multicast emerges. Multicast is a method for a host to send a message to multiple specific recipients, and becomes an indispensable key technology on the new generation network.
The basic conception of the Internet Protocol (IP, a network interconnection protocol) multicast is: A source host sends only one copy of data, and the destination address in the data is the address of a multicast group. All recipients in the multicast group can receive the same copy of data, and only a host (destination host) in the multicast group can receive the data, and other hosts on the network cannot receive it. IP addresses are categorized into four classes, namely, classes A-D. Class D addresses are reserved as multicast addresses. In IPv4, all IP addresses from 224.0.0.0 to 239.255.255.255 are class D addresses. Addresses from 224.0.0.0 to 224.0.0.255 are reserved. Addresses from 224.0.1.0 to 238.255.255.255 are multicast addresses for users and are valid on the entire network. Addresses from 239.0.0.0 to 239.255.255.255 are administratively scoped multicast addresses and are valid in the specific local scope. On an IPv4 multicast network, how to use addresses other than known and reserved multicast addresses is not specified. Therefore, addresses may conflict.
Most Internet Protocol Television (IPTV) services are developed using multicast technologies. In the IPTV operation in a prior art, multiple IPTV operators may share one bearer network, as shown in FIG. 1. In the scenario, a User Equipment (UE) obtains the multicast address of a channel from an Electronic Program Guide (EPG) provided by an IPTV operator, and then initiates a multicast request according to the multicast address.
Multicast addresses provided by different IPTV operators may be the same, and multicast paths of most programs of one IPTV operator may also be the same. Therefore, a conflict may occur. To solve the conflict problem, channels of each IPTV operator may be allocated different multicast addresses. If each channel requires one IP multicast address, the bearer network needs to maintain many multicast paths. Thus, the maintenance burden is very heavy.
In a prior art that enables a network operator to manage multicast addresses in a unified manner, the network operator allocates multicast addresses to channels of an IPTV operator and provides an EPG in a unified manner, thus ensuring that multicast addresses on the bearer network do not conflict. To a certain degree, the solution solves the possible multicast address conflict problem when multiple IPTV operators share one bearer network.
During the process of implementing the present invention, the inventor finds that the prior art has at least the following weakness:
If multicast addresses of channels of an IPTV operator are allocated by a network operator, multicast addresses of channels of the IPTV operator can hardly be consistent when the network of the IPTV operator needs to be connected to multiple bearer networks. The bearer network still needs to maintain many multicast paths.